Hoist System Research Articles

Pitch stability analysis of high-lift wire rope hoist vertical shiplift under shallow water sloshing–structure interaction

Pitch stability under shallow water sloshing–structure interaction has always been the most concerned issue in the design of the high-lift wire rope hoist vertical shiplift, which brings great challenges to the operational safety. A semi-analytical method including the developed modal system and the new coupled dynamics model is presented for pitch stability analysis. Based on the linear modal theory, the modal system is developed to describe the shallow water sloshing in the shiplift chamber, and the hydrodynamic moment associated with infinite set of modal functions is reasonably simplified by only retaining the lowest mode. Then a new 9-DOF coupled dynamics model of the complete main hoist system, shiplift chamber motion, and shallow water sloshing is established as dynamic equations by using the Lagrange equation of the second kind. Subsequently, the coefficient matrix of the dynamic equations and the Lyapunov motion stability theory are used in combination to numerically obtain the critical distance of suspension points. Taking four typical high-lift wire rope hoist shiplifts as an example, the results indicate that the proposed scheme improves the computational accuracy by 7.0–20.8% with respect to previous methods. Furthermore, for the being designed 200 m level wire rope hoist vertical shiplift, the preliminary design parameters can ensure the pitch stability safety factor not less than 1.3, increasing the wire rope stiffness or the synchronous shaft stiffness can effectively enhance the pitch stability.

Linear Permanent Magnet Eddy Current Brake for Overwinding Protection

Overwinding protection devices are used to brake hoisting containers before these containers reach a limited height, thereby preventing the hoisting containers from impacting the hoisting system. However, in ultra-deep shafts (depth > 1000 m), traditional overwinding protection methods fail to protect the hoisting system, because this type of hoisting system has a greater mass, kinetic energy, and inertia than the traditional hoisting system, and also the environment of ultra-deep shafts is more complex. This paper presents a novel overwinding protection method that applies a linear permanent magnet eddy current brake (LPMECB) to the hoisting system in ultra-deep shafts. This paper also finds the optimum setting parameter of permanent magnets (PMs). First, an analytical model of the LPMECB is built, and the time-domain signals of the braking force are processed via fast Fourier transform, confirming the mechanism of the optimum setting parameter. Subsequently, the simulations are conducted by establishing a finite-element model of the LPMECB; the simulations prove the existence of the optimum setting parameter of PMs and demonstrate the influence of the air gap, velocity, and conductivity on this parameter. Finally, the experimental studies are carried out on a test bench of the LPMECB to validate the analytical model and the simulation results. The results show the existence of the optimum setting parameter of PMs and prove that the air gap has an effect on this parameter.

Nonlinear Dynamic Behavior of Winding Hoisting Rope under Head Sheave Axial Wobbles

Axial wobbles of the head sheave due to manufacturing accuracy and installation technology can exert periodic lateral excitations to the winding hoisting rope. A hoisting rope consists of a constant catenary rope from the drum to the head sheave and a variable vertical rope from the head sheave to the conveyance. The longitudinal and lateral vibration responses of the hoisting rope are coupled to each other. In this paper, the coupled lateral‐longitudinal governing equations of the winding hoisting system under the axial wobble excitations of the head sheave are established by the Hamilton principle. The governing equations are nonlinear infinite‐dimensional partial differential equations, which are discretized into the finite‐dimensional ordinary differential equations through the Galerkin method. The dynamic responses of the hoisting rope under the head sheave axial wobbles are given by MATLAB simulation when the winding hoist is lifting or lowering. The results show that lateral vibration displacements of the vertical rope under the head sheave axial wobbles are larger than those of the catenary rope. The axial wobble amplitude range of the head sheave is given to limit the lateral vibration displacements of the hoisting rope.

A Remote Monitoring and Diagnosis Method Based on Four-Layer IoT Frame Perception

In this study, a real-time remote monitoring and fault diagnosis method has been developed based on the Internet of Things (IoT) frame perception, and successfully applied to a mine hoist system. The proposed method combines the sensor technology, online monitoring technology, wireless transmission technology, and fault diagnosis technology. The basic structure of the traditional IoT comprises a perception layer, a network layer, and an application layer, the proposed structure contains an additional middleware layer between the network layer and the application layer. This four-layer system is used in a mine hoist remote monitoring and fault diagnosis framework to process heterogeneous multi-source information. The sensors and parameters are connected in the perception layer, the characteristic parameters are obtained using the configuration software, and the mine local area network is saved to the data server, thereby synchronizing real-time data in the local area network. The network layer utilizes mature Internet and long-distance wireless transmission communication technologies, whereas the middleware layer comprises of a Service-Oriented Architecture (SOA)-based IoT data processing framework that integrates the multi-source heterogeneous data. Further, the fault diagnosis method is analyzed and verified based on the gray association rules. In the application layer, a human-computer interface is used for the remote monitoring and diagnosis of the mine hoist and to provide the diagnosis results as feedback to the user. The results using the aforementioned analyses are applied to the remote monitoring and diagnosis of a mine hoist system. In this study, experimental tests are conducted in this study to significantly improve the fault monitoring, diagnostic capabilities, and reliability of the mine hoist system, indicating the good application good prospects of the proposed method.

Fault Diagnosis of Mine Shaft Guide Rails Using Vibration Signal Analysis Based on Dynamic Time Warping

Guide rails are amongst the most important components of mine hoist systems, and faults in them must be detected as early as possible to avoid fatal breakdowns in mine production. Presently, guide rail inspection is performed visually in most situations. In this paper, we examine a more efficient approach based on multi-time scale and dynamic time warping (DTW) to diagnose guide rail faults including embossment, bumps, and clearance. Firstly, vibration signals collected from operational conveyance under different fault categories are analyzed and the corresponding characteristic waveforms (CWs) are extracted. Embossment faults are identified with priority according to visible disparities in CW patterns on a large time scale. Then, templates for bump and clearance faults are established through processing the CWs on a small time scale. Subsequently, the distances of DTW (DDTWs) between test samples and the selected templates are calculated. Finally, the remaining fault conditions are classified according to the DDTW results since the same fault category has the smallest distance. Experiments are conducted on a guide rail fault simulator to demonstrate the reliability of the proposed method. The resultant diagnosis accuracies are 100%, 90.40%, and 84.53%, respectively, for embossment, bump, and clearance faults, which indicates that the proposed approach is feasible and effective for diagnosing guide rail faults under variable operating conditions and different fault severities.

Breaking failure analysis and finite element simulation of wear-out winding hoist wire rope

Abstract Surface wear is the main reason for the breaking failure of the wire rope in service, particularly in the multi-layer winding hoist system of a coal mine. Understanding the effect of wear scars on the failure and mechanical properties of the rope is the effective way to ensure the safety of multi-layer winding hoist. In this paper, the breaking failure characteristics of hoist ropes with different wear scars were investigated by the breaking tensile test. The temperature rise in the wear scar regions was obtained and analyzed. Additionally, the finite element method was used to simulate the mechanical properties of the wear-out strands subjected to tensile load. Results show that the severe plastic deformation and obvious temperature rise occur in the wear scar region. The temperature rise curves during the breaking tensile test can reflect the number and the order of the fractured strands. The wear-out outer wires fracture earlier than the internal wires, and the wires with irregular wear scar always fracture along the sliding wear direction at the location with the maximum wear depth. Additionally, the wear scar caused by left cross contact will cause stress concentration and uneven distribution, and the wear depth makes it more obvious.

Independent hoisting system: structural components, lifting mechanism, crane control

Independent hoisting system: structural components, lifting mechanism, crane control

The study on crossover layouts of multi-layer winding grooves in deep mine hoists based on transverse vibration characteristics of catenary rope

In a deep mine winding hoist system, the lateral oscillation of the catenary rope is an important evaluation index of orderly rope arrangement and engineering safety. Different boundary excitations will appear when the wire rope winds on symmetrical or asymmetrical grooves, which results in the different dynamic responses of the hoisting system. In this article, the vibration equations of a deep mine hoisting system are established by using the Hamilton principle, and excitation functions of different crossover zone layouts are deduced. The operation curves are introduced to conduct the experiment based on a certain experimental platform. The lateral oscillation of the catenary rope is recorded by high-speed cameras, and an effective image processing method is proposed to obtain the vibration response of a certain point in the catenary rope. The numerical simulations are compared with the experimental results to prove the vibration models derived in this article are valid. The models could provide reliable basis for the grooves type selection in deep mine hoisting.

Parameter Sensitivity Analysis and Probabilistic Optimal Design for the Main-Shaft Device of a Mine Hoist

As a key component of a mine hoist system, the main-shaft device bears most of the bending moment and torque. Thus, it is important to quantify the performance of the main-shaft device and ensure the reliability of the device. The paper aims to investigate the impact of uncertain structural parameters on the reliability of the main-shaft device. The probabilistic optimal design is performed based on the parameter sensitivity results. First, the design of experiments is adopted to realize the stochastic response analysis of the main-shaft device. Second, the moment-based saddlepoint approximation method is used to evaluate the strength reliability of the device considering uncertain parameters. Next, the reliability-based sensitivity is derived to investigate the parametric significance of random input variables. Finally, the probabilistic optimal design involving the reliability sensitivity is conducted. The results of the sensitivity indicate that the torque and the contact length of left bearing have relatively greater impact on the structural reliability than other variables of the main-shaft device.

The sensitivity of the hoist system in crane applications from speed control methods at induction motor

Choosing the appropriate control technique in variable speed drive (VSD) is very important to avoid faults on the hoisting system of molten metal. This paper analyzes the sensitivity of the hoist system in crane applications from the three various control techniques of variable speed drives of induction motors: V/f open-loop control, V/f closed-loop control and closed-loop vector control. It is noticed that stoppages of motor run are usually caused by the wrong selection of control technique, by overload (overcurrent and overvoltage) or by both. On the V/f control (open and closed-loop), when the load is 45 t in low output speed (5–6 Hz), the hook is moving without control downward direction, even if the command was given for lifting (upward direction), therefore we cannot use this control technique on the main hoist 50 T Crane. In the closed-loop vector control, the feedback error information determines the exact voltage vector position and norm to produce exactly what is needed to correct the error, as the result of the number of fault/trip on hoist crane applications will be minimal. For different loads, although the output currents change obviously, motor temperature remains constant.

Investigation of the Energy Regeneration and Control Strategy of a Crane Hoisting System

Investigation of the Energy Regeneration and Control Strategy of a Crane Hoisting System

Parameter estimation for BLDCM in rescue hoist drive and reduction of torque ripple and winding loss using conditional extremum current model

Brushless dc motor (BLDCM) presents excellent performance in rescue hoist drive because of its high power&torque density. The development of control strategies greatly improve torque ripple and winding loss of BLDCM respectively. However, it is still a challenge to promote comprehensive performance of hoist system such as loss and vibration etc. in the unified control framework. To solve this problem, a comprehensive control strategy of phase current optimization to reduce winding loss and torque ripple simultaneously for BLDCM that utilizing phase current continuous conduction and estimated back-electromotive force (EMF) is proposed. Firstly, with the electromagnetic torque as the constraint, a conditional extremum model of phase current is built to obtain the minimal solution of three-phase reference current. Secondly, considering non-ideal characteristics of the actual back-EMF wave, a sliding-mode observer is designed to estimate the wave online. Experiment results show that under the same load condition, the torque ripple ratio, winding loss and the current harmonics are all lower in proposed strategy than those inconventional two-phase conduction method. Good performance can be achieved by employing the proposed method in non flux-weakening application like the hoisting.

Hierarchical Modeling and Dynamic Analysis of Hoist System in Electric Mining Shovel

The hoist system of electric mining shovel (EMS) always encounters excessive vibration in present work. However, the shortage of suitable dynamic model has been the bottleneck of reducing vibration. In order to analyze the vibration of the EMS hoist system, a coupled dynamic model is proposed using the hierarchical modeling method, which contains couplings of bolt, bear, coupling, rope, and gear mesh. The components were equivalent to mass elements with several nodes corresponding to their structure. Considered helical gears and motors, a dynamic gear transmission model with couplings of bending, torsion, and axes was developed. Based on the dynamic model, the modal characteristics were calculated, and the vibration modes were classified to five types. Under the ripple drive torque simulated by Simulink, the dynamic characteristics of the hoist system in time domain and frequency domain were obtained using numerical integration with the Runge–Kutta method in Matlab. At last, the model validity was verified by contrasting the responses under actual test and the model. The dynamic model and study results can provide support for dynamic characteristic evaluation and dynamic optimization of the EMS hoist system.

The efficacy of the electric patient hoist systems in mobilization.

OBJECTIVE:Long-term immobilization brings about physiological and biomechanical adverse effects on organs and systems. For enabling patients to stand on their feet and to be mobilized in the early period, electric patient hoist system (EPHS) accelerates the recovery of systemic functions and allows the patient with neurological diseases to become independent. This study aimed to investigate whether EPHS differs from conventional systems in the duration of hospitalization, mobility level and return to activities of daily living by analyzing patients mobilized with EPHS in the early period.METHODS:We analyzed 30 patients with neurological diseases, who were aged 50-75 years and immobile for more than one week. The patients were divided into two groups as EPHS patients and controls. Before and after the treatment, we recorded age, height, weight, hospitalization duration and time of mobilization. Mobility was assessed using the clinical and Rivermead mobility indexes while daily activities were evaluated with the Barthel index.RESULTS:Our results indicated that the hospitalization duration decreased significantly in the patients practicing with EPHS in comparison with the controls (p=0.014). When the groups were compared regarding the pre- and post-treatment outcomes of the clinical and Rivermead mobility indexes, the mobility levels of the EPHS group showed more considerable improvement (p<0.001). The Barthel index demonstrated that the EPHS patients showed significantly higher participation in daily life within a significantly shorter time (p=0.002).CONCLUSION:Applying EPHS in the early period of hospitalization extends the time patients stand on their feet, enabling them to spend this time effectively. In conclusion, intervening immobile patients with EPHS in addition to their early rehabilitation program achieved earlier mobilization, shorter hospitalization and easier return to daily life activities.

Vibration modal shapes and strain measurement of the main shaft assembly of a friction hoist

In order to evaluate the reliability of the main shaft unit of a friction hoisting system, strain measurement is a significant method. In this paper, a test rig of a friction hoisting system was built, which could applied periodically changing load on its main shaft unit; The mechanical analysis under the test load was conducted and the boundary limits were obtained; A three dimensional model of the main shaft unit was built in Pro-E and its finite element analysis was performed in ANSYS; With the analytical result, measuring points for strain rosettes were initially selected; Vibration modal shapes of the main shaft unit were analyzed, based on which Modal Assurance Criterion (MAC) was utilized in the Particle Swarm Optimization (PSO) algorithm to make the final decision of the number and positions of the measuring points; A wireless measurement system was developed to acquire strain signals from the optimized measuring positions; The test result verified the efficiency of the methods employed in this paper and revealed how strain of the main shaft unit changes during running process.

Longitudinal dynamic characteristics of steel wire rope in a friction hoisting system and its coupling effect with friction transmission

Abstract The longitudinal rope dynamics in a friction hoisting system and its coupling effect with friction transmission are investigated. The tension and longitudinal vibration characteristics of the rope are obtained through experiments. The dynamics of rope and friction transmission are obtained by a validated simulation model. The results show that the rope tension is divided into the dynamic tension regime and inertial tension regime due to the multi-frequency cross-linking. The longitudinal rope vibration is embodied as random perturbation. The reduction of the friction coefficient will increase the sliding between the rope and lining, and it will be beneficial to narrowing the dynamic tension regime. The increase in the longitudinal rope vibration will reduce the friction force between the rope and lining.

Multi-body dynamics co-simulation of hoisting wire rope

As more wire ropes with complex construction are used in the hoisting system of a crane, it becomes more necessary to predict the risks of the hoisting operation. Especially the wire rope, dynamic analysis is required to manage the potential risk in advance. Thus, in this article, a co-simulation method based on multi-body dynamics and finite element method is proposed to determine the dynamic responses of a hoisting system and wire rope. We developed a dynamic model of hoisting system based on ADAMS/Cable to formulate the time history response of dynamic force on wire rope, which could be used as the loading condition in the posterior finite element model. A three-dimensional geometric model for the multi-layered strands wire rope with a construction of 1+7+7 / 7+14 wires is implemented in the finite element analysis software ABAQUS, and both static and dynamic analyses are presented. The static analysis result of force–strain relation is compared with several experiment data, and the finite element model is proved accurate and reliable. In the latter case, the force–time curves obtained by dynamic model are imported to finite element model as loading condition to accomplish dynamic analysis. The co-simulation results of hoisting wire rope’s behavior subjected to dynamic loading during the hoisting process are carried out and discussed. The stress distribution and stress spectrum of wire rope are obtained, and the results show that the most dangerous regions are the lateral side of wire rope, especially the contact area of two wires in strands.

Wire rope tension control of hoisting systems using a robust nonlinear adaptive backstepping control scheme

This paper concerns wire rope tension control of a double-rope winding hoisting system (DRWHS), which consists of a hoisting system employed to realize a transportation function and an electro-hydraulic servo system utilized to adjust wire rope tensions. A dynamic model of the DRWHS is developed in which parameter uncertainties and external disturbances are considered. A comparison between simulation results using the dynamic model and experimental results using a double-rope winding hoisting experimental system is given in order to demonstrate accuracy of the dynamic model. In order to improve the wire rope tension coordination control performance of the DRWHS, a robust nonlinear adaptive backstepping controller (RNABC) combined with a nonlinear disturbance observer (NDO) is proposed. Main features of the proposed combined controller are: (1) using the RNABC to adjust wire rope tensions with consideration of parameter uncertainties, whose parameters are designed online by adaptive laws derived from Lyapunov stability theory to guarantee the control performance and stability of the closed-loop system; and (2) introducing the NDO to deal with uncertain external disturbances. In order to demonstrate feasibility and effectiveness of the proposed controller, experimental studies have been conducted on the DRWHS controlled by an xPC rapid prototyping system. Experimental results verify that the proposed controller exhibits excellent performance on wire rope tension coordination control compared with a conventional proportional-integral (PI) controller and adaptive backstepping controller.

Reliability Analysis of the Main-Shaft Device of a Hoist System with Coupling Faults

In this paper, the reliability and reliability sensitivity of the main shaft device of a hoist system is studied. The main purpose of this paper is to provide a modeling method for the joint probability distribution of main shaft device with coupling faults based on the system reliability theory and copula function theory. The stochastic response of the main shaft device is obtained using design of experiment. The reliability of the main shaft device is calculated based on the fourth moment method. The reliability sensitivity is then deduced based on the reliability results. The joint probability of failure between correlated failure modes is estimated based on the Gumbel copula. The system reliability evaluation of the main shaft device is then calculated. A numerical example of a main shaft device is illustrated to validate the application of the proposed method. The method proposed in this study can be provided for the analysis and design of the main shaft device of deep well hoist as a necessary theoretical basis.

Super Capacitor Energy Storage Based MMC for Energy Harvesting in Mine Hoist Application

This paper proposes a super capacitor energy storage-based modular multilevel converter (SCES-MMC) for mine hoist application. Different from the conventional MMCs, the sub-modules employ distributed super capacitor banks, which are designed to absorb the regenerative energy of mine hoist and released in the traction condition, so as to improve energy utilization efficiency. The key control technologies are introduced in detail, followed by analysis of the configuration and operation principles. The feasibility of the proposed SCES-MMC topology and the control theory are also verified. Simulation results show that SCES-MMC can adapt to the variable frequency speed regulation of the motor drive, which shows good application prospects in the future for medium- and high-voltage mine hoist systems.